1. Technical Field Relating to the Invention
This invention relates to an electrical contactor and an electrical connecting apparatus that are for example applicable as an electrical contactor to contact an electrode provided in a wiring substrate, a semiconductor integrated circuit or the like and an electrical connecting apparatus having multiple electrical contactors.
2. Background of Related Art
A well-known electrical contactor is to electrically connect electrical circuits on wiring substrates arranged to face each other, for example. An example of such an electrical contactor can be found in patent document 1 (Japanese Patent Laid-Open No. 2013-7730) (in patent document 1, the electrical contactor is called a probe).
FIG. 10 is a vertical sectional view showing an electrical contactor 1 described in patent document 1. The vertical section of FIG. 10 is cut at a plane passing through the central axis of the electrical contactor 1.
The electrical contactor 1 has a conductive barrel 2 and a conductive plunger 3. The barrel 2 has a substantially cylindrical shape. The barrel 2 has two spring parts including a spring part 2b and a spring part 2d that exert elastic forces in the vertical direction (longitudinal direction). Specifically, the barrel 2 has an upper part 2a, the upper spring part 2b, an intermediary part 2c, the lower spring part 2d, and a lower part 2e arranged in this order as viewed from the top. The plunger 3 has a substantially cylindrical columnar shape. The inner diameter of the barrel 2 and the outer diameter of the plunger 3 is substantially the same. The plunger 3 is mostly inserted in internal space of the barrel 2. The plunger 3 is inserted in the internal space of the barrel 2 such that the upper end of the plunger 3 does not protrude outside the barrel 2 from the upper part 2a regardless of the presence or absence of application of external force on the electrical contactor 1. A lower part of the plunger 3 protrudes downward further than the lower part 2e of the barrel 2. The lower part 2e and the plunger 3 are bonded and fixed to each other for example by resistance welding, laser welding, or swaging in a position (indicating not one point but several points or a circle) P at a given height of the lower part 2e of the barrel 2.
For use of the electrical contactor 1 integrated in an electrical connecting apparatus, the upper end of the barrel 2 is electrically connected to an external electrode or the like not shown in the drawings above the barrel 2 and the lower end of the plunger 3 is electrically connected to an external electrode or the like not shown in the drawings below the plunger 3 while the spring parts 2b and 2d of the barrel 2 store energy and exert elastic forces in the vertical direction in response to application of external force.